<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="utf-8" />
  <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <meta name="theme-color" content="#000000" />
  <meta name="description" content="Web site created using create-react-app" />
  <script>
    (function (win, lib) {
      var doc = win.document;
      var docEl = doc.documentElement;
      var metaEl = doc.querySelector('meta[name="viewport"]');
      var flexibleEl = doc.querySelector('meta[name="flexible"]');
      var dpr = 0;
      var scale = 0;
      var tid;
      var flexible = lib.flexible || (lib.flexible = {});

      if (metaEl) {
        console.warn('将根据已有的meta标签来设置缩放比例');
        var match = metaEl.getAttribute('content').match(/initial\-scale=([\d\.]+)/);
        if (match) {
          scale = parseFloat(match[1]);
          dpr = parseInt(1 / scale);
        }
      } else if (flexibleEl) {
        var content = flexibleEl.getAttribute('content');
        if (content) {
          var initialDpr = content.match(/initial\-dpr=([\d\.]+)/);
          var maximumDpr = content.match(/maximum\-dpr=([\d\.]+)/);
          if (initialDpr) {
            dpr = parseFloat(initialDpr[1]);
            scale = parseFloat((1 / dpr).toFixed(2));
          }
          if (maximumDpr) {
            dpr = parseFloat(maximumDpr[1]);
            scale = parseFloat((1 / dpr).toFixed(2));
          }
        }
      }
      if (!dpr && !scale) {
        var isAndroid = win.navigator.appVersion.match(/android/gi);
        var isIPhone = win.navigator.appVersion.match(/iphone/gi);
        var devicePixelRatio = win.devicePixelRatio;
        if (isIPhone) {
          // iOS下，对于2和3的屏，用2倍的方案，其余的用1倍方案
          if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) {
            dpr = 3;
          } else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)) {
            dpr = 2;
          } else {
            dpr = 1;
          }
        } else {
          // 其他设备下，仍旧使用1倍的方案
          dpr = 1;
        }
        scale = 1 / dpr;
      }
      docEl.setAttribute('data-dpr', dpr);
      if (!metaEl) {
        metaEl = doc.createElement('meta');
        metaEl.setAttribute('name', 'viewport');
        metaEl.setAttribute('content', 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' +
          scale + ', user-scalable=no');
        if (docEl.firstElementChild) {
          docEl.firstElementChild.appendChild(metaEl);
        } else {
          var wrap = doc.createElement('div');
          wrap.appendChild(metaEl);
          doc.write(wrap.innerHTML);
        }
      }

      function refreshRem() {
        var width = docEl.getBoundingClientRect().width;
        if (width / dpr > 540) {
          width = 540 * dpr;
        }
        var rem = width / 10;
        docEl.style.fontSize = rem + 'px';
        flexible.rem = win.rem = rem;
      }
      win.addEventListener('resize', function () {
        clearTimeout(tid);
        tid = setTimeout(refreshRem, 300);
      }, false);
      win.addEventListener('pageshow', function (e) {
        if (e.persisted) {
          clearTimeout(tid);
          tid = setTimeout(refreshRem, 300);
        }
      }, false);
      if (doc.readyState === 'complete') {
        doc.body.style.fontSize = 12 * dpr + 'px';
      } else {
        doc.addEventListener('DOMContentLoaded', function (e) {
          doc.body.style.fontSize = 12 * dpr + 'px';
        }, false);
      }

      refreshRem();
      flexible.dpr = win.dpr = dpr;
      flexible.refreshRem = refreshRem;
      flexible.rem2px = function (d) {
        var val = parseFloat(d) * this.rem;
        if (typeof d === 'string' && d.match(/rem$/)) {
          val += 'px';
        }
        return val;
      }
      flexible.px2rem = function (d) {
        var val = parseFloat(d) / this.rem;
        if (typeof d === 'string' && d.match(/px$/)) {
          val += 'rem';
        }
        return val;
      }
    })(window, window['lib'] || (window['lib'] = {}));
  </script>
  <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
  <!--
      manifest.json provides metadata used when your web app is installed on a
      user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
    -->
  <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
  <!--
      Notice the use of %PUBLIC_URL% in the tags above.
      It will be replaced with the URL of the `public` folder during the build.
      Only files inside the `public` folder can be referenced from the HTML.

      Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
      work correctly both with client-side routing and a non-root public URL.
      Learn how to configure a non-root public URL by running `npm run build`.
    -->
  <title>React App</title>
</head>

<body>
  <noscript>You need to enable JavaScript to run this app.</noscript>
  <div id="root"></div>
  <!--
      This HTML file is a template.
      If you open it directly in the browser, you will see an empty page.

      You can add webfonts, meta tags, or analytics to this file.
      The build step will place the bundled scripts into the <body> tag.

      To begin the development, run `npm start` or `yarn start`.
      To create a production bundle, use `npm run build` or `yarn build`.
    -->
</body>

</html>